U.S. patent number 9,112,135 [Application Number 13/538,432] was granted by the patent office on 2015-08-18 for piezoelectric element and method for manufacturing piezoelectric element.
This patent grant is currently assigned to TDK CORPORATION. The grantee listed for this patent is Noriaki Hirano, Mitsunao Homma, Masahiro Kitajima, Nobuo Kobayashi, Masaru Nanao. Invention is credited to Noriaki Hirano, Mitsunao Homma, Masahiro Kitajima, Nobuo Kobayashi, Masaru Nanao.
United States Patent |
9,112,135 |
Kobayashi , et al. |
August 18, 2015 |
Piezoelectric element and method for manufacturing piezoelectric
element
Abstract
A piezoelectric element is provided with an element body, which
has a pair of principal faces opposed to each other and an end face
extending in a direction in which the pair of principal faces are
opposed to each other, so as to connect the pair of principal
faces, and which is comprised of a piezoelectric ceramic material;
a pair of electrodes arranged respectively on the pair of principal
faces; and a resin covering an entire area of the end face and
arranged so as to make contact with the pair of electrodes. The
resin has two edges in the aforementioned direction projecting
outward in the aforementioned direction from the respective
electrodes.
Inventors: |
Kobayashi; Nobuo (Tokyo,
JP), Hirano; Noriaki (Tokyo, JP), Nanao;
Masaru (Tokyo, JP), Kitajima; Masahiro (Tokyo,
JP), Homma; Mitsunao (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Kobayashi; Nobuo
Hirano; Noriaki
Nanao; Masaru
Kitajima; Masahiro
Homma; Mitsunao |
Tokyo
Tokyo
Tokyo
Tokyo
Tokyo |
N/A
N/A
N/A
N/A
N/A |
JP
JP
JP
JP
JP |
|
|
Assignee: |
TDK CORPORATION (Tokyo,
JP)
|
Family
ID: |
47438235 |
Appl.
No.: |
13/538,432 |
Filed: |
June 29, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130009520 A1 |
Jan 10, 2013 |
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Foreign Application Priority Data
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Jul 8, 2011 [JP] |
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2011-152107 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
41/053 (20130101); H01L 41/338 (20130101); H01L
41/23 (20130101); H01L 41/0986 (20130101); H01L
41/0533 (20130101); G11B 5/4873 (20130101); Y10T
29/42 (20150115) |
Current International
Class: |
H01L
41/22 (20130101); H01L 41/09 (20060101); H01L
41/053 (20060101); G11B 5/48 (20060101); H01L
41/23 (20130101); H01L 41/338 (20130101) |
Field of
Search: |
;310/328,365,363,364,366 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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A-2010-192010 |
|
Sep 2010 |
|
JP |
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2011-514608 |
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May 2011 |
|
JP |
|
Primary Examiner: Rosenau; Derek
Assistant Examiner: Gordon; Bryan
Attorney, Agent or Firm: Oliff PLC
Claims
What is claimed is:
1. A piezoelectric element comprising: an element body which has a
pair of principal faces opposed to each other, and four end faces
extending in a direction in which the pair of principal faces are
opposed to each other, so as to connect the pair of principal
faces, the element body is comprised of a piezoelectric ceramic
material, the element body has a rectangular parallelepiped shape;
a pair of electrodes arranged respectively on the pair of principal
faces, the respective electrodes each having a rectangular shape in
a plan view, the respective electrodes each having four sides; and
a resin covering an entire area of the four end faces and arranged
so as to make contact with each of the four sides of each of the
pair of electrodes, wherein the resin has two edges in said
direction projecting outward in said direction from the respective
electrodes.
2. The piezoelectric element according to claim 1, wherein at least
one of the two edges of the resin covers a region near the end
faces in a surface of the electrode, along an edge of the
electrode.
3. The piezoelectric element according to claim 1, wherein the end
faces of the element body and respective end faces of the pair of
electrodes are aligned in position as cut faces.
4. A head suspension having a piezoelectric element, the
piezoelectric element comprising: an element body which has a pair
of principal faces opposed to each other, and four end faces
extending in a direction in which the pair of principal faces are
opposed to each other, so as to connect the pair of principal
faces, the element body is comprised of a piezoelectric ceramic
material, the element body has a rectangular parallelepiped shape;
a pair of electrodes arranged respectively on the pair of principal
faces, the respective electrodes each having a rectangular shape in
a plan view, the respective electrodes each having four sides; and
a resin covering an entire area of the four end faces and arranged
so as to make contact with each of the four sides of each of the
pair of electrodes, wherein the resin has two edges in said
direction projecting outward in said direction from the respective
electrodes, and wherein the piezoelectric element is fixed to the
head suspension with an adhesive.
5. The piezoelectric element according to claim 4, wherein at least
one of the two edges of the resin covers a region near the end face
in a surface of the electrode, along an edge of the electrode.
6. The piezoelectric element according to claim 4, wherein the end
faces of the element body and respective end faces of the pair of
electrodes are aligned in position as cut faces.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a piezoelectric element and a
method for manufacturing the piezoelectric element.
2. Related Background Art
A known piezoelectric element is one provided with an element body,
which has a pair of principal faces opposed to each other and end
faces extending in a direction in which the pair of principal faces
are opposed to each other, so as to connect the pair of principal
faces, and which is comprised of a piezoelectric ceramic material,
and with a pair of electrodes arranged respectively on the pair of
principal faces (e.g., cf. Japanese Patent Application Laid-open
No. 2010-192010).
SUMMARY OF THE INVENTION
The piezoelectric element described in the Laid-open No.
2010-192010 has the problems as described below.
Since the element body is comprised of the piezoelectric ceramic
material, crystal grains thereof can drop off from the end faces of
the element body. When the piezoelectric element is used in a head
suspension for disk device as described in the Laid-open No.
2010-192010, the dropping crystal grains can enter a space between
a disk and a slider forming a magnetic head. The crystal grains
entering the space between the disk and the slider forming the
magnetic head can cause damage to the disk and the slider.
Furthermore, delamination can occur easily between the element body
and the electrodes. The element body is comprised of the
piezoelectric ceramic material and the electrodes are comprised of
a metal material. Since the element body and the electrodes are
made of the different materials, the occurrence of delamination is
unavoidable at interfaces between the element body and the
electrodes.
An object of the present invention is to provide a piezoelectric
element capable of preventing the crystal grains from dropping off
from the end faces of the element body and preventing the
occurrence of delamination between the element body and the
electrodes, and a method for manufacturing the piezoelectric
element.
A piezoelectric element according to the present invention is a
piezoelectric element comprising: an element body which has a pair
of principal faces opposed to each other, and an end face extending
in a direction in which the pair of principal faces are opposed to
each other (which will be referred to hereinafter as "opposed
direction"), so as to connect the pair of principal faces, and
which is comprised of a piezoelectric ceramic material; a pair of
electrodes arranged respectively on the pair of principal faces;
and a resin covering an entire area of the end face and arranged so
as to make contact with the pair of electrodes, wherein the resin
has two edges in the opposed direction projecting outward in the
opposed direction from the respective electrodes.
In the present invention, the entire area of the end face of the
element body is covered by the resin. For this reason, crystal
grains are prevented from dropping off from the end face of the
element body. In the present invention, the pair of electrodes are
in contact with the resin. For this reason, the electrodes are
prevented from delaminating from the element body.
In the present invention, the two edges of the resin covering the
entire area of the end face of the element body are arranged to
project outward in the opposed direction from the respective
electrodes. For this reason, when the piezoelectric element is
fixed to another member with an adhesive, the piezoelectric element
is arranged so that either one of the principal faces (electrodes)
is located on the other member side. At this time, since the two
edges of the resin are arranged to project as described above,
there is a relatively large gap formed between a surface of the
electrode and the other member. This gap can be used as an adhesive
pool, whereby the adhesion strength is improved between the
piezoelectric element and the other member.
At least one of the two edges of the resin may cover a region near
the end face in a surface of the electrode, along an edge of the
electrode. In this case, the contact area between the electrode and
the resin is increased, whereby the electrode is prevented more
securely from delaminating from the element body.
The end face of the element body and respective end faces of the
pair of electrodes may be aligned in position as cut faces. In this
case, it becomes easier to achieve contact between the electrodes
and the resin.
A manufacturing method of a piezoelectric element according to the
present invention is a method for manufacturing a piezoelectric
element, comprising: a preparation step of preparing a
piezoelectric element substrate having a pair of principal faces
opposed to each other and having electrodes formed on the pair of
principal faces; an attachment step of attaching a tape with
adhesion to one of the principal faces of the piezoelectric element
substrate; a substrate cutting step of cutting the piezoelectric
element substrate from the other principal face side of the
principal faces of the piezoelectric element substrate and removing
a portion of the tape; a resin filling step of filling a channel
formed by the cutting step, with a resin so that the resin is in
contact with each of the electrodes and is arranged to project
outward in the opposed direction from the electrode formed on the
other principal face; a resin cutting step of cutting the resin
from the other principal face side; and a peeling step of peeling
the tape off from the piezoelectric element substrate.
In the manufacturing method of the piezoelectric element according
to the present invention, the substrate cutting step is to remove a
portion of the tape, the resin filling step is to fill the channel
with the resin so as to bring the resin in contact with each of the
electrodes and so as to project the resin outward in the opposed
direction from the electrode formed on the other principal face,
and the resin cutting step is to cut the resin. Through this
process, the entire area of the cut face of the piezoelectric
element substrate is covered by the resin. For this reason, crystal
grains are prevented from dropping off from the cut face of the
piezoelectric element substrate. Since the resin is in contact with
the pair of electrodes, the electrodes are prevented from
delaminating from the piezoelectric element substrate.
Since a portion of the tape is removed, the resin comes to project
outward in the opposed direction, not only from the electrode
formed on the other principal face, but also from the electrode
formed on the one principal face. For this reason, as described
above, the adhesion strength is improved between the manufactured
piezoelectric element and the other member.
The resin filling step may comprise filling the resin so as to
cover a region near a cut face in a surface of the electrode formed
on the other principal face, along an edge of the electrode. In
this case, the contact area increases between the electrode formed
on the other principal face and the resin, whereby the electrode is
prevented more securely from delaminating from the element
body.
The substrate cutting step may comprise removing a portion of the
tape so as to form a space between a region near a cut face in a
surface of the electrode formed on the one principal face, and the
tape, and the resin filling step may comprise filling the space
thus formed, with the resin. In this case, the contact area
increases between the electrode formed on the one principal face
and the resin, whereby the electrode is prevented more securely
from delaminating from the element body.
The present invention will become more fully understood from the
detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become
apparent from the detailed description given hereinafter. However,
it should be understood that the detailed description and specific
examples, while indicating preferred embodiments of the invention,
are given by way of illustration only, since various changes and
modifications within the spirit and scope of the invention will
become apparent to those skilled in the art from this detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a piezoelectric element
according to an embodiment of the present invention.
FIG. 2 is a drawing explaining a cross-sectional configuration of
the piezoelectric element according to the embodiment.
FIG. 3 is a flowchart showing a method for manufacturing the
piezoelectric element according to the embodiment.
FIG. 4 is schematic views for explaining the manufacturing method
of the piezoelectric element according to the embodiment.
FIG. 5 is a drawing showing an example in which the piezoelectric
element of the embodiment is fixed to another member.
FIG. 6 is a drawing explaining a cross-sectional configuration of a
piezoelectric element according to a modification example of the
embodiment.
FIG. 7 is schematic views for explaining a method for manufacturing
the piezoelectric element according to the modification example of
the embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the present invention will be
described below in detail with reference to the accompanying
drawings. In the description, the same elements or elements with
the same functionality will be denoted by the same reference signs,
without redundant description.
First, a configuration of a piezoelectric element 1 according to an
embodiment of the present invention will be described with
reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing
the piezoelectric element according to the present embodiment. FIG.
2 is a drawing explaining a cross-sectional configuration of the
piezoelectric element according to the present embodiment.
The piezoelectric element 1, as shown in FIG. 1, is provided with
an element body 3, a pair of first electrode 5 and second electrode
7, and a resin 9. The piezoelectric element 1 is applied, for
example, to a disk device with a magnetic disk. Namely, the
piezoelectric element 1 is used as a second actuator except for a
voice coil motor in the disk device of a dual actuator system.
The element body 3 has a pair of first principal face 3a and second
principal face 3b, and end faces 3c. The first principal face 3a
and the second principal face 3b are opposed to each other. The end
faces 3c extend in a direction in which the first principal face 3a
and the second principal face 3b are opposed to each other (which
will sometimes be referred to hereinafter simply as "opposed
direction"), so as to connect the first principal face 3a and the
second principal face 3b. The element body 3 has a rectangular
parallelepiped shape. Therefore, the element body 3 has a
rectangular shape on a plan view and thus has four end faces 3c.
The element body 3 is comprised of a piezoelectric ceramic
material. Examples of piezoelectric ceramic materials applicable
herein include PZT [Pb(Zr,Ti)O.sub.3], PT(PbTiO.sub.3),
PLZT[(Pb,La)(Zr,Ti)O.sub.3], barium titanate (BaTiO.sub.3), and so
on.
The first electrode 5 is arranged on the first principal face 3a so
as to cover the entire area of the first principal face 3a. The
second electrode 7 is arranged on the second principal face 3b so
as to cover the entire area of the second principal face 3b. The
end faces 3c are not covered by the electrodes. The first electrode
5 and the second electrode 7 are comprised of a metal material such
as Au. The first electrode 5 and the second electrode 7 can be
formed, for example, by sputtering, evaporation, or the like.
The resin 9 covers the entire area of the end faces 3c. The resin 9
is arranged on the end faces 3c so as to make contact with the
first electrode 5 and the second electrode 7. An epoxy resin is
used as a material of the resin 9. Besides the epoxy resin, a
thermosetting resin such as urethane resin can be employed. It is
also possible to use an ultraviolet curable resin such as epoxy
acrylate resin or urethane acrylate resin. It is also possible to
use a hot-melt resin such as polyvinyl acetate.
The resin 9 has two edges 9a, 9b in the opposed direction
projecting outward in the opposed direction from the respective
electrodes 5, 7. Namely, the two edges 9a, 9b of resin 9 are
arranged to project away from the respective electrodes 5, 7 in the
opposed direction. The edge 9a of resin 9 covers a region near the
end faces 3c in the surface of the first electrode 5, along the
edge of the first electrode 5.
Next, a manufacturing method of the piezoelectric element 1
according to the present embodiment will be described with
reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the
manufacturing method of the piezoelectric element according to the
present embodiment. In FIG. 4, (a) to (f) are schematic views for
explaining the manufacturing method of the piezoelectric element
according to the present embodiment.
First, a piezoelectric element substrate 11 is prepared (S101). The
piezoelectric element substrate 11 is provided with a substrate
portion 13 comprised of a piezoelectric ceramic material, a first
electrode 15, and a second electrode 17 (cf. (a) in FIG. 4).
Specifically, the piezoelectric element substrate 11 has a
platelike shape, in a state in which a plurality of piezoelectric
elements 1 (except without the resin 9) in an
individually-separated state are connected.
The substrate portion 13 has a pair of first principal face 13a and
second principal face 13b opposed to each other. The first
electrode 15 is formed on the first principal face 13a and the
second electrode 17 is formed on the second principal face 13b.
When the piezoelectric element substrate 11 is separated into
individual piezoelectric elements, the first electrode 15 turns to
the first electrodes 5 and the second electrode 17 to the second
electrodes 7. The first electrode 15 and second electrode 17 are
comprised of a metal material such as Au and are formed, for
example, by sputtering or evaporation.
The next process is to prepare a tape 21 consisting of an
ultraviolet-curable dicing tape (S103). The tape 21 includes an
ultraviolet-curable adhesive layer 21a on its surface and has an
adhesive property.
The next process is to attach the tape 21 to the second electrode
17 of the piezoelectric element substrate 11 (S105). In this
process, the second electrode 17 is attached to the adhesive layer
21a of the tape 21 (cf. (b) in FIG. 4).
The next process is to cut the piezoelectric element substrate 11
(S107). In this process, the piezoelectric element substrate 11 is
diced from the first electrode 15 side with a blade W1 to form
channels CH1 in the piezoelectric element substrate 11 (cf. (c) in
FIG. 4). When the piezoelectric element substrate 11 is cut, the
tape 21 is half cut so that a portion of the tape 21 is removed
from the adhesive layer 21a side. The thickness of the blade W1
(i.e., the width of the channels CH1) is set, for example, in the
range of about 20 to 1000 .mu.m. There are no particular
restrictions on the depth of the half cut of the tape 21, but the
depth is preferably determined so as to leave a portion of the
adhesive layer 21a in portions of the channels CH1. The depth of
the half cut of tape 21 is set, for example, in the range of about
1 to 50 .mu.m.
Cut faces of the substrate portion 13 become the aforementioned end
faces 3c. Cut faces of the first electrode 15 become end faces of
the first electrodes 5, and cut faces of the second electrode 17
become end faces of the second electrodes 7. Since the first
electrode 15 and second electrode 17 are also cut together with the
substrate portion 13, the positions of the cut faces of the
respective electrodes 15, 17 (the end faces of the respective
electrodes 5, 7) are aligned with the positions of the cut faces of
the substrate portion 13 (end faces 3c).
Next, the channels CH1 are filled with a resin 19 (S109). A filling
method with the resin 19 employed herein can be, for example,
printing, dipping, application by a dispenser, or spin coating. The
channels CH1 are entirely filled with the resin 19, whereby the
resin covers the cut faces of the respective electrodes 15, 17 and
the cut faces of the substrate portion 13. Thereafter, the resin 19
is cured (cf. (d) in FIG. 4).
The resin 19 filled in the channels CH1 is in contact with the tape
21. This causes the resin 19 to be so filled as to project outward
in the opposed direction of the first principal face 13a and the
second principal face 13b from the second electrode 17, and the
resin 19 is cured in the projecting state. Furthermore, the resin
19 is so filled as to cover regions near the cut faces in the
surface of the first electrode 15, along edges of the first
electrode 15. This causes the resin 19 to be so filled as to
project outward in the opposed direction from the first electrode
15, and the resin 19 is cured in the projecting state.
Next, the resin 19 is cut from the first electrode 15 side (S111).
In this process, the resin 19 is diced from the first electrode 15
side with a blade W2 to form channels CH2 (cf. (e) in FIG. 4). This
process results in cutting the resin 19 and the piezoelectric
element substrate 11 is separated into individual piezoelectric
elements in a state in which the cut faces of the respective
electrodes 15, 17 and the cut faces of the substrate portion 13 are
covered by the resin 19.
The tape 21 is also half cut. The thickness of the blade W2 (i.e.,
the width of the channels CH2) is smaller than that of the blade W1
and is set, for example, in the range of about 10 to 400 .mu.m. By
this setting, the thickness of the resin 19 covering the cut faces
comes to fall in the range of about 5 to 450 .mu.m.
Next, the tape 21 is peeled off from the piezoelectric element
substrate 11 (S113). In this process, the tape is irradiated with
ultraviolet light to decrease the adhesion of the adhesive layer
21a and then the tape 21 is peeled off from the piezoelectric
element substrate 11. This process results in obtaining
individually-separated piezoelectric elements 1 (cf. (f) in FIG.
4). Namely, the substrate portion 13 turns to the element bodies 3,
the electrodes 15, 17 turn to the electrodes 5, 7, respectively,
and the resin 19 turns to the resin 9. The irradiation with
ultraviolet light may be carried out after the substrate cutting
process S107. In this case, the processes after the substrate
cutting process S107 are carried out in a state in which the
adhesion of the adhesive layer 21a is lowered.
In the piezoelectric element 1 of the present embodiment, as
described above, the entire area of the end faces 3c of the element
body 3 is covered by the resin 9. For this reason, crystal grains
are prevented from dropping off from the end faces 3c of the
element body 3. In the piezoelectric element 1, the first electrode
5 and the second electrode 7 are in contact with the resin 9. For
this reason, the first electrode 5 and the second electrode 7 are
prevented from delaminating from the element body 3.
In the piezoelectric element 1, the two edges 9a, 9b of the resin 9
covering the entire area of the end faces 3c of the element body 3
are arrange to project outward in the opposed direction from the
respective electrodes 5, 7. For this reason, when the piezoelectric
element 1 is fixed to another member (e.g., a head suspension) 31
with an adhesive 33 as shown in FIG. 5, the piezoelectric element 1
is arranged so that either one of the principal faces 3a, 3b
(electrodes 5, 7) is located on the other member 31 side. In FIG.
5, the piezoelectric element 1 is arranged so that the second
principal face 3b (second electrode 7) is located on the other
member 31 side. At this time, since the edge 9b of the resin 9 is
arranged to project as described above, there is a relatively large
gap formed between the surface of the second electrode 7 and the
other member 31. This gap can be used as an adhesive pool, so as to
enhance the adhesion strength between the piezoelectric element 1
and the other member 31.
When the other member 31 consists of an electrically conductive
member, it is necessary to ensure electrical insulation between the
electrodes 5, 7 of the piezoelectric element 1 and the other member
31. For this reason, conventionally, the adhesive 33 used is one
containing a filler. The filler functions to adjust the distance
between the electrode 5 or 7 on the other member 31 side and the
other member 31.
In use of the filler-containing adhesive, however, there is
variation in size of the filler and therefore it was difficult
heretofore to adjust the distance between the electrode 5 or 7 on
the other member 31 side and the other member 31 to an appropriate
value and difficult to ensure electrical insulation. The
filler-containing adhesive is more expensive than adhesives
containing no filler. In contrast to it, the present embodiment
employs the configuration wherein the edges 9a, 9b of the resin 9
are arranged to project as described above, the distance between
the surface of the electrode 5, 7 and the other member 31 is
appropriately and readily adjusted. Accordingly, the electrical
insulation between the piezoelectric element 1 and the other member
31 is suitably and inexpensively ensured.
In the piezoelectric element 1, the edge 9a of the resin 9 covers
the region near the end faces 3c in the surface of the first
electrode 5, along the edge of the first electrode 5. This
configuration increases the contact area between the first
electrode 5 and the resin 9, whereby the first electrode 5 is
prevented more securely from delaminating from the element body
3.
The end faces 3c of the element body 3 and the corresponding end
faces of the respective electrodes 5, 7 are aligned in position as
cut faces. This facilitates contact between each electrode 5, 7 and
the resin 9.
Next, a configuration of the piezoelectric element 1 according to a
modification example of the embodiment will be described with
reference to FIG. 6. FIG. 6 is a drawing explaining a
cross-sectional configuration of the piezoelectric element
according to the modification example of the embodiment.
In the piezoelectric element 1 of the modification example, the
edge 9b of the resin 9 covers a region near the end faces 3c in the
surface of the second electrode 7, along the edge of the second
electrode 7.
Next, a manufacturing method of the piezoelectric element 1
according to the modification example will be described with
reference to FIG. 7. In FIG. 7, (a) to (c) are schematic views for
explaining the manufacturing method of the piezoelectric element
according to the modification example of the embodiment.
The piezoelectric element 1 of the modification example is also
manufactured through the processes S101-S113 in the manufacturing
method shown in FIG. 3, but it is different from the above
embodiment in that the edge 9b of the resin 9 is formed as
described below.
The piezoelectric element substrate 11 is cut to remove a portion
of the adhesive layer 21a (S107). At this time, as shown in (a) in
FIG. 7, a portion of the adhesive layer 21a adjacent to the blade
W1 (portion attached to the region near the cut faces in the second
electrode 17) is deformed with progress of the blade W1. This
process results in forming a space S between the region near the
cut faces in the surface of the second electrode 17 and the tape
21.
Next, the channels CH1 are filled with the resin 19 (S109). At this
time, as shown in (b) in FIG. 7, the channels all are filled with
the resin 19 so that the resin 19 comes into contact with the tape
21. Therefore, the space S is also filled with the resin 19 and the
resin 19 is cured in a state in which the space S is filled
therewith. This causes the resin 19 to be so filled and cured as to
cover the region near the cut faces in the surface of the second
electrode 17, along the edge of the second electrode 17.
Thereafter, the resin 19 is cut from the first electrode 15 side
(S111) and the tape 21 is peeled off from the piezoelectric element
substrate 11 (S113), thereby obtaining individually-separated
piezoelectric elements 1, as shown in (c) in FIG. 7.
In the present modification example, as described above, crystal
grains are prevented from dropping off from the end faces 3c of the
element body 3 and the first electrode 5 and the second electrode 7
are prevented from delaminating from the element body 3. The
present modification example also improves in adhesion strength
between the piezoelectric element 1 and the other member 31.
Furthermore, in the present modification example, the edge 9b of
the resin 9 covers the region near the end faces 3c in the surface
of the second electrode 7, along the edge of the second electrode
7. This configuration increases the contact area between the second
electrode 7 and the resin 9, whereby the second electrode 7 is
prevented more securely from delaminating from the element body
3.
The above described the preferred embodiments of the present
invention, but it should be noted that the present invention is by
no means intended to be limited to the above embodiments and can be
modified in many ways without departing from the scope and spirit
of the invention.
For example, the planar shape of the piezoelectric element 1
(element body 3) does not have to be limited to the rectangular
shape shown in FIG. 1, but it can be arbitrarily modified according
to places to which the piezoelectric element 1 is applied.
From the invention thus described, it will be obvious that the
invention may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended for inclusion within the scope of the
following claims.
* * * * *